River Wear, Durham City: The bane of hop pickers, the pale tussock moth larva isn’t normally found precariously wandering along a bridge

“Wait a minute, what was that?” We retraced our steps, astonished. A pale tussock moth larva, inching its way along the parapet of Prebends bridge, had chosen the most precarious route possible to wander in search of somewhere to pupate. Gusting wind, sending withered leaves tumbling across the bridge, threatened to blow it into the river, 30 feet below.

My wife, more dextrous than I, coaxed the caterpillar into the collecting tube I always carry in my pocket. Immediately it curled into a defensive ball covered in rosettes of long, neon green whiskers, with a mane of bristles, four dense tufts like miniature shaving brushes on its back, and a menacing spike of rose-pink hairs at the tail. Everything about it warned “don’t touch me”.